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<body>
    <p>合并单元格1和单元格5: colspan</p>
    <p>合并单元格7和单元格8: rowspan</p>
    <p>水平合并：保留左边，删除右边</p>
    <p>垂直合并：保留上边，删除下边</p>
    <table border="1" width="500" height="300">
        <tr>
            <td rowspan="2">单元格1</td>
            <td>单元格2</td>
            <td>单元格3</td>
            <td>单元格4</td>
        </tr>
        <tr>
            
            <td>单元格6</td>
            <td colspan="2">单元格7</td>
        </tr>
        <tr>
            <td>单元格9</td>
            <td>单元格10</td>
            <td>单元格11</td>
            <td>单元格12</td>
        </tr>
        <tr>
            <td>单元格13</td>
            <td>单元格14</td>
            <td>单元格15</td>
            <td>单元格16</td>
        </tr>
    </table>
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